The effect of contrast agent reduction on the image quality of pulmonary Computed Tomography

Evaluation of contrast agent reduction on the image quality of pulmonary Computed Tomography using a standard reconstruction available in the conventional CT system

Status

Recruiting

Phases

Phase 3

Study type

Interventional

Source

IRCT

Registry ID

IRCT20220313054273N2

Enrollment

Registered

2022-09-27

Start date

2022-09-23

Completion date

Unknown

Last updated

2022-11-21

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

pulmonary thromboembolism. Pulmonary embolism

Interventions

Intervention 1: Intervention group: Patients suspected of pulmonary embolism referred to Namazi Hospital (Shiraz) will be scanned by contrast agent reduction protocol. The amount of injected contrast

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Inclusion criteria

Inclusion criteria: Suspicion pulmonary emboly as seen from clinical indication Abnormal levels of plasma D-dimer Lower extremity deep vein thrombosis

Exclusion criteria

Exclusion criteria: Severe pneumonia and atelectasis Confirmed pregnancy or suspected but unconfirmed pregnancy Critically ill patient or patients hospitalized in ICU Allergy to iodine contrast agents Creatinine>1.36 mg/dL Age < 18 years GFR less than 60ml/min/1.73m2 Body-Mass Index (BMI) greater than 30 kg/m2

Design outcomes

Primary

Measure	Time frame
The objective image quality of pulmonary CT Angio will be determined by radiologists through a scoring system. The quantitative image quality will be determined by quantitative parameters such as Signal-to-Noise Ratio. Timepoint: The CT images will be sent to Picture Archiving and Communication System immediately after the scanning procedure completed. Then the qualitative and quantitative evaluation of the image quality of pulmonary CT Angio will be performed. Method of measurement: Quantitative pulmonary Computed Tomography angiography (CTA) image quality will be measured by the Signal-to-Noise Ratio (SNR). The mean CT density or CT- number of the main pulmonary arteries (left and right) will be measured. The CT-numbers will be measured by selecting the Region of Interest (ROI) inside the left and right main pulmonary arteries, filled with the contrast agent. This CT number is known as signal. The muscles surrounding the scapula is known as background, being a region without contrast agent. An ROI will be selected in the background. Then, the standard deviation of the CT-number will be measured for the background. These measured parameters will be used to calculate SNR. Qualitative pulmonary CT Angio (CTA) image quality will be measured by visual assessment. In this method, two expert radiologists will report the image quality using a scoring system. In this system measuring the image quality is measured in a scale of 5 in which the scores assigned as follows, (1) undiagnosable (2) limited diagnostic value (3) sufficient diagnostic value (4) good image quality (5) excellent diagnostic value. If the mean score equal to or greater than 3, it will be reported as an acceptable diagnostic value.	—

Measure

Time frame

The objective image quality of pulmonary CT Angio will be determined by radiologists through a scoring system. The quantitative image quality will be determined by quantitative parameters such as Signal-to-Noise Ratio. Timepoint: The CT images will be sent to Picture Archiving and Communication System immediately after the scanning procedure completed. Then the qualitative and quantitative evaluation of the image quality of pulmonary CT Angio will be performed. Method of measurement: Quantitative pulmonary Computed Tomography angiography (CTA) image quality will be measured by the Signal-to-Noise Ratio (SNR). The mean CT density or CT- number of the main pulmonary arteries (left and right) will be measured. The CT-numbers will be measured by selecting the Region of Interest (ROI) inside the left and right main pulmonary arteries, filled with the contrast agent. This CT number is known as signal. The muscles surrounding the scapula is known as background, being a region without contrast agent. An ROI will be selected in the background. Then, the standard deviation of the CT-number will be measured for the background. These measured parameters will be used to calculate SNR. Qualitative pulmonary CT Angio (CTA) image quality will be measured by visual assessment. In this method, two expert radiologists will report the image quality using a scoring system. In this system measuring the image quality is measured in a scale of 5 in which the scores assigned as follows, (1) undiagnosable (2) limited diagnostic value (3) sufficient diagnostic value (4) good image quality (5) excellent diagnostic value. If the mean score equal to or greater than 3, it will be reported as an acceptable diagnostic value.

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Countries

Iran (Islamic Republic of)

Contacts

Public ContactRezvan Ravanfar Haghighi

Shiraz University of Medical Sciences

sravanfarr@gmail.com+98 71 3628 1464

Outcome results

None listed

Source: IRCT (via WHO ICTRP) · Data processed: Feb 4, 2026